package com.ms_square.etsyblur;

import android.graphics.Bitmap;
import android.os.AsyncTask;
import android.os.Debug;
import android.support.annotation.NonNull;
import android.support.annotation.Nullable;
import android.util.Log;

import java.util.Locale;

/**
 * JavaFastBlur.java
 *
 * @author Manabu-GT on 3/22/17.
 */
class JavaFastBlur extends BaseBlurEngine {

    private static final String TAG = JavaFastBlur.class.getSimpleName();

    public JavaFastBlur(@NonNull BlurConfig blurConfig) {
        super(blurConfig);
    }

    @Override
    public Bitmap execute(@NonNull Bitmap inBitmap, boolean canReuseInBitmap) {
        return fastBlur(inBitmap, blurConfig.radius(), canReuseInBitmap);
    }

    @Override
    public Bitmap execute(@NonNull Bitmap inBitmap, @NonNull Bitmap outBitmap) {
        return fastBlur(inBitmap, outBitmap, blurConfig.radius());
    }

    @Override
    public void execute(@NonNull Bitmap inBitmap, boolean canReuseInBitmap, @NonNull Callback callback) {
        if (shouldAsync(inBitmap.getWidth(), inBitmap.getHeight(), blurConfig.radius())) {
            asyncTasks.add(new FastBlurAsyncTask(inBitmap, null, canReuseInBitmap, callback).execute(blurConfig));
        } else {
            callback.onFinished(fastBlur(inBitmap, blurConfig.radius(), canReuseInBitmap));
        }
    }

    @Override
    public void execute(@NonNull Bitmap inBitmap, @NonNull Bitmap outBitmap, @NonNull Callback callback) {
        if (shouldAsync(inBitmap.getWidth(), inBitmap.getHeight(), blurConfig.radius())) {
            asyncTasks.add(new FastBlurAsyncTask(inBitmap, outBitmap, callback).execute(blurConfig));
        } else {
            callback.onFinished(fastBlur(inBitmap, outBitmap, blurConfig.radius()));
        }
    }

    @Override
    public String methodDescription() {
        return "Java's FastBlur implementation";
    }

    @Override
    long calculateComputation(int bmpWidth, int bmpHeight, int radius) {
        return bmpHeight * (2 * radius + bmpWidth) + bmpWidth * (2 * radius + bmpHeight);
    }

    @Override
    boolean shouldAsync(int bmpWidth, int bmpHeight, int radius) {
        return blurConfig.asyncPolicy().shouldAsync(false, calculateComputation(bmpWidth, bmpHeight, radius));
    }

    private Bitmap fastBlur(Bitmap inBitmap, int radius, boolean canReuseInBitmap) {
        Bitmap outBitmap;
        if (canReuseInBitmap) {
            outBitmap = inBitmap;
        } else {
            outBitmap = inBitmap.copy(inBitmap.getConfig(), true);
        }

        return fastBlur(inBitmap, outBitmap, radius);
    }

    // Ref...http://stackoverflow.com/questions/2067955/fast-bitmap-blur-for-android-sdk
    private Bitmap fastBlur(Bitmap inBitmap, Bitmap outBitmap, int radius) {

        // Stack Blur v1.0 from
        // http://www.quasimondo.com/StackBlurForCanvas/StackBlurDemo.html
        //
        // Java Author: Mario Klingemann <mario at quasimondo.com>
        // http://incubator.quasimondo.com
        // created Feburary 29, 2004
        // Android port : Yahel Bouaziz <yahel at kayenko.com>
        // http://www.kayenko.com
        // ported april 5th, 2012

        // This is a compromise between Gaussian Blur and Box blur
        // It creates much better looking blurs than Box Blur, but is
        // 7x faster than my Gaussian Blur implementation.
        //
        // I called it Stack Blur because this describes best how this
        // filter works internally: it creates a kind of moving stack
        // of colors whilst scanning through the image. Thereby it
        // just has to add one new block of color to the right side
        // of the stack and remove the leftmost color. The remaining
        // colors on the topmost layer of the stack are either added on
        // or reduced by one, depending on if they are on the right or
        // on the left side of the stack.
        //
        // If you are using this algorithm in your code please add
        // the following line:
        //
        // Stack Blur Algorithm by Mario Klingemann <mario@quasimondo.com>

        long start = Debug.threadCpuTimeNanos();

        if (radius < 1) {
            return null;
        }

        int w = inBitmap.getWidth();
        int h = inBitmap.getHeight();

        int[] pix = new int[w * h];
        inBitmap.getPixels(pix, 0, w, 0, 0, w, h);

        int wm = w - 1;
        int hm = h - 1;
        int wh = w * h;
        int div = radius + radius + 1;

        int r[] = new int[wh];
        int g[] = new int[wh];
        int b[] = new int[wh];
        int rsum, gsum, bsum, x, y, i, p, yp, yi, yw;
        int vmin[] = new int[Math.max(w, h)];

        int divsum = (div + 1) >> 1;
        divsum *= divsum;
        int dv[] = new int[256 * divsum];
        for (i = 0; i < 256 * divsum; i++) {
            dv[i] = (i / divsum);
        }

        yw = yi = 0;

        int[][] stack = new int[div][3];
        int stackpointer;
        int stackstart;
        int[] sir;
        int rbs;
        int r1 = radius + 1;
        int routsum, goutsum, boutsum;
        int rinsum, ginsum, binsum;

        for (y = 0; y < h; y++) {
            rinsum = ginsum = binsum = routsum = goutsum = boutsum = rsum = gsum = bsum = 0;
            for (i = -radius; i <= radius; i++) {
                p = pix[yi + Math.min(wm, Math.max(i, 0))];
                sir = stack[i + radius];
                sir[0] = (p & 0xff0000) >> 16;
                sir[1] = (p & 0x00ff00) >> 8;
                sir[2] = (p & 0x0000ff);
                rbs = r1 - Math.abs(i);
                rsum += sir[0] * rbs;
                gsum += sir[1] * rbs;
                bsum += sir[2] * rbs;
                if (i > 0) {
                    rinsum += sir[0];
                    ginsum += sir[1];
                    binsum += sir[2];
                } else {
                    routsum += sir[0];
                    goutsum += sir[1];
                    boutsum += sir[2];
                }
            }
            stackpointer = radius;

            for (x = 0; x < w; x++) {

                r[yi] = dv[rsum];
                g[yi] = dv[gsum];
                b[yi] = dv[bsum];

                rsum -= routsum;
                gsum -= goutsum;
                bsum -= boutsum;

                stackstart = stackpointer - radius + div;
                sir = stack[stackstart % div];

                routsum -= sir[0];
                goutsum -= sir[1];
                boutsum -= sir[2];

                if (y == 0) {
                    vmin[x] = Math.min(x + radius + 1, wm);
                }
                p = pix[yw + vmin[x]];

                sir[0] = (p & 0xff0000) >> 16;
                sir[1] = (p & 0x00ff00) >> 8;
                sir[2] = (p & 0x0000ff);

                rinsum += sir[0];
                ginsum += sir[1];
                binsum += sir[2];

                rsum += rinsum;
                gsum += ginsum;
                bsum += binsum;

                stackpointer = (stackpointer + 1) % div;
                sir = stack[(stackpointer) % div];

                routsum += sir[0];
                goutsum += sir[1];
                boutsum += sir[2];

                rinsum -= sir[0];
                ginsum -= sir[1];
                binsum -= sir[2];

                yi++;
            }
            yw += w;
        }
        for (x = 0; x < w; x++) {
            rinsum = ginsum = binsum = routsum = goutsum = boutsum = rsum = gsum = bsum = 0;
            yp = -radius * w;
            for (i = -radius; i <= radius; i++) {
                yi = Math.max(0, yp) + x;

                sir = stack[i + radius];

                sir[0] = r[yi];
                sir[1] = g[yi];
                sir[2] = b[yi];

                rbs = r1 - Math.abs(i);

                rsum += r[yi] * rbs;
                gsum += g[yi] * rbs;
                bsum += b[yi] * rbs;

                if (i > 0) {
                    rinsum += sir[0];
                    ginsum += sir[1];
                    binsum += sir[2];
                } else {
                    routsum += sir[0];
                    goutsum += sir[1];
                    boutsum += sir[2];
                }

                if (i < hm) {
                    yp += w;
                }
            }
            yi = x;
            stackpointer = radius;
            for (y = 0; y < h; y++) {
                // Preserve alpha channel: ( 0xff000000 & pix[yi] )
                pix[yi] = (0xff000000 & pix[yi]) | (dv[rsum] << 16) | (dv[gsum] << 8) | dv[bsum];

                rsum -= routsum;
                gsum -= goutsum;
                bsum -= boutsum;

                stackstart = stackpointer - radius + div;
                sir = stack[stackstart % div];

                routsum -= sir[0];
                goutsum -= sir[1];
                boutsum -= sir[2];

                if (x == 0) {
                    vmin[y] = Math.min(y + r1, hm) * w;
                }
                p = x + vmin[y];

                sir[0] = r[p];
                sir[1] = g[p];
                sir[2] = b[p];

                rinsum += sir[0];
                ginsum += sir[1];
                binsum += sir[2];

                rsum += rinsum;
                gsum += ginsum;
                bsum += binsum;

                stackpointer = (stackpointer + 1) % div;
                sir = stack[stackpointer];

                routsum += sir[0];
                goutsum += sir[1];
                boutsum += sir[2];

                rinsum -= sir[0];
                ginsum -= sir[1];
                binsum -= sir[2];

                yi += w;
            }
        }

        outBitmap.setPixels(pix, 0, w, 0, 0, w, h);

        if (start > 0) {
            long duration = Debug.threadCpuTimeNanos() - start;
            blurConfig.asyncPolicy().putSampleData(false, calculateComputation(w, h, radius), duration);
            if (blurConfig.debug()) {
                Log.d(TAG, String.format(Locale.US, "fastBlur() took %d ms.", duration / 1000000L));
            }
        }

        return outBitmap;
    }

    class FastBlurAsyncTask extends AsyncTask<BlurConfig, Void, Bitmap> {

        private final Bitmap inBitmap;
        private final Bitmap outBitmap;
        private final boolean canReuseInBitmap;
        private final Callback callback;

        public FastBlurAsyncTask(@NonNull Bitmap inBitmap, @Nullable Bitmap outBitmap,
                                 @NonNull Callback callback) {
            this(inBitmap, outBitmap, false, callback);
        }

        public FastBlurAsyncTask(@NonNull Bitmap inBitmap, @Nullable Bitmap outBitmap,
                                 boolean canReuseInBitmap, @NonNull Callback callback) {
            this.inBitmap = inBitmap;
            this.outBitmap = outBitmap;
            this.canReuseInBitmap = canReuseInBitmap;
            this.callback = callback;
        }

        @Override
        protected Bitmap doInBackground(BlurConfig... params) {
            BlurConfig config = params[0];
            if (isCancelled()) {
                return null;
            }
            if (blurConfig.debug()) {
                Log.d(TAG, "Running in background...");
            }
            if (outBitmap != null) {
                return fastBlur(inBitmap, outBitmap, config.radius());
            } else {
                return fastBlur(inBitmap, config.radius(), canReuseInBitmap);
            }
        }

        @Override
        protected void onCancelled(Bitmap blurredBitmap) {
            asyncTasks.remove(this);
        }

        @Override
        protected void onPostExecute(Bitmap blurredBitmap) {
            callback.onFinished(blurredBitmap);
            asyncTasks.remove(this);
        }
    }
}
